New Phaser Design - “Causality 4” – Built with you in mind!

[Mark Hammer]

I have the pedals with a phase-filter setting, two Ross/Ropez pedals, and a Small Stone Clone.  Two use the same cap values for lowpass as the allpass, and one uses a smaller cap value.

When the cap value is the same for lowpass and allpass, more of the mids and highs are attenuated, which has the effect of reducing the overall signal amplitude (when in wet-only),  That's part of what gets the strange mélange of vibrato, tremolo, and modulated-wah.  Of course, it also drops the "intelligibility" of the wet signal because all those mids and highs are gone.  With a smaller cap value, more of the lower mids remain, which improves clarity but attenuates the tremolo-like modulation of overall amplitude.

Your choice.  Neither is "better", just a different kind of sound.

[tubelectron]

Hi Rick,

You may remember this one :





and this :

Quote from: tubelectron on November 03, 2010, 03:51:29 AM

1 - When the regen control approaches the max (3/4), it saturates and the rate is somewhat "wobbled".
2 - Sometimes there is "clicks" at the rate of the LFO, like if it's wave was clipped.

Rick : do you know how to get rid of these 2 problems ?

A+!


I'll work on it! I'm currently building a couple of Causality 6, so I'll experiment a bit

About which I have no news from you...
Building pedal is good, but building them with no functioning issues is better...
So, where is the problem and what are the mods I can do by myself on the circuit to get rid of thse issue, as above ?
No such problem occurs with my Phase90, my SmallStone 1978 or my PFA Morley.

Sorry to be insistant, Rick, but the pedal you've built for me isn't usable as is !

Thanks for your help,

A+!

[frequencycentral]

Hey Bruno, I wasn't aware your pedal was unusable, or I would of course take it back. I've got Causality back on the breadboard to sort out a few issues and make some other improvements. A few things you can do yourself:

• Replace the resistor voltage divider R1/R2 with a 78L05. This will make the vref dead solid.
• Replace R33 (10k) with a socket. Try 47k or 100k in it's place

It may be the LED indicator is causing ticking in your unit. Disconnect and see if it goes away.

Anyway, I'm happy to do this work for you if you want to sent the unit back to me. And, lets use PM rather than this thread to discuss it please.

Rick

[tubelectron]

OK, Rick,

Hey Bruno, I wasn't aware your pedal was unusable, or I would of course take it back. I've got Causality back on the breadboard to sort out a few issues and make some other improvements. A few things you can do yourself:


•Replace the resistor voltage divider R1/R2 with a 78L05. This will make the vref dead solid.
•Replace R33 (10k) with a socket. Try 47k or 100k in it's place

It may be the LED indicator is causing ticking in your unit. Disconnect and see if it goes away.

The question is not to return the instrument to you, but having directions from the designer on how to fix some issues to make the unit functioning properly to be usable, and I am sure that the informations given here will be of a great interest to the other C4Mk2 owners or builders to make their unit work flawlessly... Didn't I said in my previous posts here that otherwise the C4Mk11 was an unusually featured and good sounding phaser, by the way ?

Nonetheless, thanks Rick for your reply - Of course I'll let you know if these solutions are satisfactory, or if I found anything else / or even better...

A+!

[mäk]

i built it from sundgist layout, but when i turn the regenpot or the dephtpot to far, i got a totally bass distorted sound! 
does some got an idea whats up with my built? checked it twice, can't find a mistake!

thanks mäk

[frequencycentral]

http://dl.dropbox.com/u/967492/No%20Quarter.mp3

Audio path:

Rick's fingers >>> Rhodes 73 MkI >>> Causality 6 >>> Roland Bolt 60 watt tube combo >>> Shure SM58 >>> Wavelab

[Valoosj]

Wow, sounds great!

[merlinb]

http://dl.dropbox.com/u/967492/No%20Quarter.mp3
Audio path:
Rick's fingers >>> Rhodes 73 MkI >>> Causality 6 >>> Roland Bolt 60 watt tube combo >>> Shure SM58 >>> Wavelab

Legend.

[soggybag]

Has anyone built this layout yet? I built a casualty 4 sometime ago and thought I give this a try if the layout was confirmed.

Based on Mark Hammer's addition of 2 extra stages to his build, I've made a new layout for "Causality 6" - as yet unverified, and it could do with a set of sharp eyes to check it for errors.......

Features:

• 2 extra OTA stages that can (optionally) be switched in or out via a DPDT.
• Provision to add even more stages.
• Pads for wet only mod.
• Optional odd/even stages in the regen path (parity switch).
• Input section options (R38, C12/R37)
• Polarity protection (D3).
• Pads to fit pretty much any size trimmer in the VR1 position.

This is a little speculative. I'm assuming the extra stages will work as shown, and that the parity mod will do also. My experience tells me that it will. I'm planning to use two of these PCBs for my super-duper-semi-modular Causality when I eventually get around to it.

The original Causality 4 board was 20 x 22 pads, the Causality 6 is 21 x 25 pads, just a bit bigger - nice job Rick!. It should still fit in a 1590B, though a 1590BB build will be easier, especially if all the options are incorporated.

As is customary, I am happy to receive any PCBs that folks might want to send my way!  

[frequencycentral]

I've built a couple. It has an error. Should be a 10k to vref from pin 12 of IC3. I also had issues with the vref being really low, still haven't figured out why. My fix was to omit R26 and R27 and use a 78L05 for vref instead, kludged into the general area the R26/R27 took up. I also omitted the parity switch and hooked up the 50k regen pot with odd parity at lug 1, even parity at lug 3, lug 2 to the 'Regen lug 2 (blue pad)', which works nicely, though in C4 stage mode one end of the pot (even parity) does a kind of tremolo thing, as then the regen is only over 2 stages. I do need to update this layout with the mods mentioned above and a few other value changes I made, as I'm planning for two of these PCBs to be the basis of my forthcoming Gemini Dual Core Phase Shifter.

[soggybag]

Thanks for the reply.

Let me see if I understand what is going on here.

There are stages of phase shift, two fixed and 4 swept. The first and last stages are fixed.

The swept stages seem to use the caps for phase shift while the first and last stages use a decade difference in caps.

The regen control seems to be a little more than regeneration. Looks like it's mixing the output of stages 4 and 5 back into the input of stage 1. Seems like there is always some regeneration going on.

[Beo]

Hey Rick, do you feel the odd/even parity switch on the regen path is worth having? Is the difference really audible?

Also, do you know a way to switch between three sets of stages (e.g. 4/6/8 or 4/8/12)?

[frequencycentral]

The regen control seems to be a little more than regeneration. Looks like it's mixing the output of stages 4 and 5 back into the input of stage 1. Seems like there is always some regeneration going on.

A 'normal' regen pot would be 10k, which is enough for there to be no regen at it's maximum resistance. The way I've got the regen 'mix' pot set up gives no regen in it's mid position, with the ability to dial in 'odd stages regen' at one end, 'even stages regen' at the other.

Hey Rick, do you feel the odd/even parity switch on the regen path is worth having? Is the difference really audible?

I like it a lot, two different flavours. There is a difference. I'm not aware of anyone else who's messed with multiple regen taps. Have a listen to what it can do on a 14 stage phaser: http://www.diystompboxes.com/smfforum/index.php?topic=84968.msg739608#msg739608   IMO, this kinda stuff is really interesting, breaks new ground, and is the future. 

Also, do you know a way to switch between three sets of stages (e.g. 4/6/8 or 4/8/12)?

Sure, if you hook up the output of each swept phase stage to a rotary switch, with the common going to the input of the last fixed phase stage, you can dial in any number of stages. Then look at my Sonic Death Ray design for how to configure multiple regen taps: http://www.diystompboxes.com/smfforum/index.php?topic=84968.msg715075#msg715075

There is still soooo much fun to be had with phasers........

[sundgist]

Finally got round to making up a box for this.





Had a can of glow in the dark paint so....


Have been meaning to add 2 extra stages and a filter toggle, finally able to get round to it.
Here's my vero layout.

[stringsthings]

i like that glow in the dark lettering 

[Mark Hammer]

So I have a pair of Causalities.  One uses the standard LFO and employs a daughter board with an extra 2 swept stages, and the other has but the 4 stages and the variable-LFO-shape feature.    The first one works fine, but the second produces a very audible "crunching" sound in sync with the LFO, that is not only an audible sound superimposed on the audio path, but actually impairs the clarity of the audio signal.  It's like listening to someone walk on hard snow in time with the music.  I can't for the life of me figure out what's wrong.  It is tamed somewhat by adjustment of the width and range controls, but never really goes away completely.

Any suggestions?

[frequencycentral]

Have you measured the vref? Is it stable?

[mr_deadmaxxx]

can you get the sound of all "other" phasers (mxr, boss, etc) on this pedal?

[Mark Hammer]

After 2, I would say no.  At least not without some fine tuning.  You definitely get a nice range of usable sounds, but you can't really throw all nominal component values at it and get dead-on emulation right out of the box.  There is also something to be said for the manner in which the various control elements (OTAs vs FETs) sweep through their range, producing a slightly different feel.

[bside2234]

I built the C4 version 1 and I'm getting some distortion when I pick the G and B string. When I play soft the distortion isn't very noticeable if at all. It sounds like I'm holding something metal against the strings when I'm picking. Almost like fret buzz.
I didn't substitute any IC's. I changed R7 to 1K, R12 to 47K, and C4 to 47u. I used C10K for the Regen, B25K for the Speed, and 47K for the Depth and I get nice sweeps out of each.
The Depth pot seems a little weird to me though. I can really only use it at Max. When it's below max it gets pretty muffled.
Any ideas on the distortion issue or has anyone else had this?